diff --git a/projects/kde/kdesrc-buildrc b/projects/kde/kdesrc-buildrc
index 119a9e7..14cdfb7 100644
--- a/projects/kde/kdesrc-buildrc
+++ b/projects/kde/kdesrc-buildrc
@@ -3,7 +3,7 @@ global
     branch-group kf6-qt6
 
     # we want ninja, turn off some Qt 5 things to have less dependencies
-    cmake-options -G "Ninja" -DBUILD_WITH_QT6=ON -DQT_MAJOR_VERSION=6 -DPHONON_BUILD_QT5=OFF -DBUILD_QT5=OFF
+    cmake-options -G "Ninja" -DBUILD_WITH_QT6=ON -DQT_MAJOR_VERSION=6 -DPHONON_BUILD_QT5=OFF -DBUILD_QT5=OFF -DCMAKE_AUTOGEN_PARALLEL=8
 
     # Restrict make and ninja to using no more than 8 separate compile jobs even
     # when more CPU is available, to avoid running out of memory
diff --git a/projects/kde/shell.nix b/projects/kde/shell.nix
index 700ffd3..47a5a50 100644
--- a/projects/kde/shell.nix
+++ b/projects/kde/shell.nix
@@ -1,7 +1,7 @@
 with import <nixpkgs> {};
 
 # use new clang
-let myllvm = llvmPackages_19; in
+let myllvm = llvmPackages_20; in
 
 # clang based dev env
 myllvm.stdenv.mkDerivation {
@@ -31,7 +31,7 @@ export QT_QUICK_CONTROLS_STYLE_PATH=~/projects/kde/usr/lib/qml/QtQuick/Controls.
     bison
     boost
     bzip2
-    clang-tools_19
+    clang-tools_20
     cmake
     ctags
     curl